Cold spark??

[90C350]

Ok Im just wondering if someone can answer this question?? I have my blm just about perfect or as close as needed. I have a good timing graph. What im wondering is should i reduce some of the timing in the cold spark table?? I havent touched this yet and My engine is running lean and popping a little until it warms up?? Runs great 3/4 worm etc, but seems to need less timing when cold. So since i have ramped up the timing in the main table for power etc would it make sense to reduce some of the cold timing advance??? This makes sense to me but looking for some help in this area!! Thanks

[91chevZ71]

yeah, maybe reduce it a bit. Since you increased the main spark stuff, the original coolant comp SA is on top of that, maybe too much. Increase VE a tad down low for the lean issue.?
FWIW, my truck runs lean (14-15.0 AFR) after startup for about 30-40 seconds. I've changed VE but it still wants to run lean. I suspect my fuel pump.

[90C350]

Ok thanks for verifing that for me. I figured i may have to reduce that table a little to compensate for the added spark in the main table. Just wanted to make sure thats the right thing to do

[90C350]

Ok thanks for verifing that for me. I figured i may have to reduce that table a little to compensate for the added spark in the main table. Just wanted to make sure thats the right thing to do

[Alexander]

Your vehicle is designed to run a little lean until the O2 sensors warm up enough to go into closed loop. Until the O2 sensors are operating at their desired temperature, the computer goes to a base program controlling fuel delivery, and spark timing. That's how it's designed to operate, so, don't change things too much...

[91chevZ71]

THe truck will run Open loop for a richer AFR as well as more SA when it is cold(it can handle it, the chamber is cold). It doesn't need the extra SA when hot, as well as not needing open loop for the richer AFR (closed loop, O2 sensor).
Hey 90, does the truck pop when you give it throttle? I've had my truck lean down low before, and it pretty much just coughed and sputtered until I gave it more fuel in the .bin then it smoothened out. If it's popping, could be an AE issue (not enough)?

[90C350]

Yeah im working on Ae right know and its a bit of a B6$^%. I'm still smoothing the Ve's a little but they are pretty good at part throttle and cruise now. I only have this problem when its cold first thing in the morning. By the time Engine reaches mild temps its ok. I'll figure it out eventually just wondering on every body else's opinion??

[91chevZ71]

You could richen up the open loop AFR a in the temps where it is off. I've messed with this a little and found that the BPC needs to be tits to get the open loop table AFR to match my wideband. It shouldn't pop at idle. It should die before it pops, just sitting there. Sounds like you're working through it, though

[Alexander]

Ooops. Sorry. My bad. You are right. Richer during open loop. Wow. I've gotta stop posting late at night, my boss would kill me if I said that at work...

[90C350]

Yeah i think i solved the problem!! I have had to go from a bpw of 113 for 20psi to a bpw of 120 at 20psi. This has cured a few problems all at once. Lean pop/cruise power and overall power. I think its time for bigger injectors. Im at almost 100% Ve at 16/2000 rpm at 70to90 map?? Im hovering around 98/99%. Any thoughts?? I have room to spare at the higher rpm range but thats typicall. Thanks for the help guys.